JP2884331B2 - Capillary connector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates generally to chromatographic devices and, more particularly, to a connector for a capillary column used in the device.

[0002]

BACKGROUND OF THE INVENTION Chromatographic equipment used in both gas and liquid chromatography employs a capillary column to provide a controlled passage for the substance to be analyzed. Analytical application areas include gas chromatography, liquid microbore chromatography, capillary electrophoresis, and supercritical fluid chromatography. For most analytical applications today, glass,
Metal or flexible fused silica capillary columns are used, and such capillary columns are
Typically, it has an internal dimension ranging from about 0.02 mm to 0.60 mm, and from about 0.10 mm to 0.80 mm
Outside dimensions. In some cases, similarly sized polymer capillaries are used. To repair broken columns, optimize chemical separation by connecting different column pieces, extend the columns by connecting two columns in series, and add retention gaps or protective columns For this reason, it is often necessary to join two pieces of capillary columns together. For most analytical applications, the end of the column must also be connected to the sample injector and detector.

[0003] The need for a practical utility capillary connector for chromatography applications is paramount. The connector must be usable in constant contact with chemically active substances and organic solvents.
When operating at internal pressures from zero (absolute) to thousands of pounds per square inch, there should be no leakage. The fluid in the capillary, whether liquid, gas, or supercritical, must not leak. The fluid seal provided by the connector can range from below ambient temperature to tens of degrees Celsius.
Must be stable over temperature cycles up to 0 degrees. In order to maintain a thermal equilibrium between the column and its immediate surroundings, the heat capacity must be small and the thermal conductivity must be high. To prevent degradation of the separation capacity of the capillary column, it must occupy only a small extra volume in the sample flow path and physical properties that can cause disturbances and contamination in the fluid Must be avoided. Resistance to fluid in the column / injector / detector assembly should be negligible. Finally, for convenience, the connection should be easy to make without special tools and should be reusable.

In the past, many connectors have been devised to meet the need to achieve a liquid tight connection between the ends of two capillary columns. Some such connectors include ferrules with longitudinal holes for inserting the ends of the columns to be connected together.
e) and a compression fit that mechanically compresses the ferrule to provide a liquid tight seal between the internal holes at each column end. Other connectors include a cylindrical body with an axial through hole to accommodate the end of a capillary column joined in butt connection, and each to seal each column to the body of the connector. And a polyimide sealing resin applied to an external joint between the column and the adjacent end wall of the connector. This requires a heat cure time of at least about 20 minutes. Yet another connector consists of a hollow glass tube having a double conical structure formed by first forming a cylindrical elongate bulb at an appropriate distance (e.g., 1 cm) from two outer ends. The connector has a double tapered internal hole that narrows toward its center. In use, each column end is inserted into a different one of the connector ends. The press-fit glass tube also had a ferrule and a press-fit portion at each end for sealing against the capillary column.

[0005]

Known connectors have several disadvantages. Ferrules and compression connectors require several moving parts and must be carefully assembled and disassembled. Many require a separate elastomeric seal to ensure liquid tightness. When a ferrule is used, a small piece of the column must be cut after the column is inserted into the ferrule to remove debris that may be pushed into the capillary bore. Also, all components must be chemically inert to the materials used in the analytical chromatography process and exhibit good temperature stability. This increases the cost of such a connector. To achieve the necessary fluid sealing,
The cylindrical body type connector has the disadvantage of requiring a minimum finite curing time for resin bonding. In addition to this, to ensure that there are no gaps or cracks in the adhesive, that the adhesive completely covers the joint to be sealed, and that the adhesive does not enter the lumen of the capillary, The polyimide resin must be carefully applied. In addition, this type of connector cannot be easily reused once the seal has been broken and one or more capillaries have been broken or cracked. Various press-fit style drawn glass double-cone connectors have been proposed, but have been reported to be particularly inconsistent with fluid seals equipped with modern hot-melt silica capillary columns. After heating to an elevated temperature, leakage is observed at the joint, and the butted end of the fused silica can be pushed further into and out of the seat. This was not possible before. A brief heating above about 200 ° C. causes the low temperature polyimide coating on the outside of the fused silica column to stick firmly to the connector walls, and violent disconnection will result in breakage of the fused silica in the seal. . Thus, there is a need for a relatively simple column connector that does not have the disadvantages of known devices.

The present invention is very simple in design and construction,
Designed to be inexpensive to manufacture, do not require an elastomeric fluid seal, include a capillary connector, allow for repeated connection / disconnection cycles, and provide quick and easy connection and disconnection operations,
The challenge is to provide the desired properties of good temperature stability, low wasted volume, chemical inertness, the ability to seal moderate gas and liquid pressures.

[0007]

SUMMARY OF THE INVENTION The present invention is a body member, preferably having a cylindrical shape, having a first end, a second end, and a tapered first end. And a body member sized to receive the end of the capillary column in a fluid-tight manner, the inner member extending between the body member and the second end. One of the first end and the second end of the body member has a curved surface that is slightly deformable when contacting the second connector, thereby providing a fluid seal without the need for a sealing gasket. I will provide a. The surface of the second connector may be flat or curved.

The body member is made of a material having high compressive strength, elasticity and inertness to chromatographic substances, which material is preferably made of zirconia. Internal holes in the body member may be provided, if necessary, to facilitate adhesion of the adhesive or to pot the compound for holding the ends of the capillary column, such as microgrooves. It has a uniform surface.

[0009] Individual connectors can be used in pairs as part of a connector assembly to form a sealed fluid connection between a pair of capillaries. The assembly includes means for keeping the pair of body members in sealed contact with one another and keeping them aligned with the curved surfaces of each body member. The maintaining means preferably comprises a split sleeve covering the ends of the pair of main body members, and means for applying a pressing force for pressing the pair of main body members so as to face each other, and the pressing force is preferably the main body. It is large enough to deform each opposing curved surface of the member.

[0010] Individual connectors may also be used in combination with a male or female portion of an injector body or liner having a flat or curved surface capable of contacting the connector to form the required deformation and fluid seal. .

In certain applications where the use of a capillary column support, such as a collet, is preferred, the body member may be provided with mounting means allowing the mounting of such a capillary column support. The means preferably includes a threaded portion on the outside of the body member adjacent one of the ends. When used, the first capillary column is inserted into the internal hole of the main body member and pressed and fitted. In the case of a capillary column coated with a protective polymer outer layer, such as a fused silica column, this forms a seal between the column end and the internal bore. Capillaries, if necessary
The body member may be permanently anchored at a predetermined position with a suitable adhesive such as glue or epoxy resin. In order to make the column removable, a column holding device such as a collet can be attached by fixing the collet or holding body to an attaching member. The second column to be connected to the first column is likewise attached to another body member, after which the two body members are brought together by the split sleeve. The two body members are then compressed such that the facing curved surface deforms and becomes flat, forming a fluid seal around the internal bore without the need for a separate sealing gasket.

In order to ensure sufficient pressing force to compress the curved surface, pressing means can be attached to the two body members. For a more complete understanding of the nature and advantages of the present invention, reference is made to the detailed description in conjunction with the accompanying drawings.

[0013]

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, FIG.
FIG. 2 is a cross-sectional view illustrating a preferred embodiment of a single body member made in accordance with the teachings of the present invention. As can be seen in this figure, the body member generally designated by reference numeral 10 has a reference numeral 12 extending between its end 14 and end 15.
Has a compound axial direction extension hole indicated by. The body member 10 is made of molded ceramic material or glass having high compressive strength, elasticity and inertness to chromatographic materials. Zirconia is one of the preferred such materials, and fused silica is another suitable equivalent. Other materials may be suitable for use in forming body member 10. In general, candidate materials must be relatively inert, must withstand reversible deformation under pressure in the area of contact, and avoid cracking under the pressure required to achieve fluid sealing Must have sufficient strength.

The axial bore 12 has a flared inlet 17 at the end 14 to facilitate insertion of the end of the capillary column in the manner described below. Most of the length 18 of the axial bore 12 tapers inward in the direction of the end 15 as shown. The remainder of the axial bore 12 comprises an essentially constant diameter portion 19.
It is. The value of the diameter of the portion 19 should be smaller than the value of the minimum outer diameter of the capillary column received in the bore 12. In a particular embodiment of the body member, the diameter of the portion 19 is 0.01000 inches plus / minus 0.0005 inches and the length of the portion 19 is.
050 inches. In the specific body member 10,
The overall angle of the widening opening 17 of the hole 12 is 40 ° plus / minus 3 °, while the overall angle of the tapered portion 18 is 3 ° plus / minus 0.5 °. For other applications of the invention, other specific dimensions apply.

The tapered portion 18 preferably has an outer diameter at the insertion end of the capillary column and a hole 12 at a point along the surface adjacent the inner end of the portion 19.
It is dimensioned to ensure an interference fit between the portion 18 and the wall surface.

An important aspect of the construction of the body member 10 that is not apparent from FIG. 1 is the contour of the inner surface 20 of the body member 10. In particular, the surface 20 has a positive radius of curvature centered about the axis of the bore 19. 2.498
For a particular body member 10 having an outer diameter in the range of 5 mm to 2.4959 mm, the radius of curvature is 20 mm as measured along the axis of the bore 19. The purpose of this positive radius of curvature will be described below.

Referring to FIG. 2, a pair of main body members 10 are provided.
A and 10B are aligned by the split sleeve 22 so that the axes are aligned. The split sleeve 22 is a generally cylindrical member having an axial slot 23 (FIG. 3) and an inner diameter slightly smaller than the outer diameter of the body members 10A, 10B. FIG.
Split sleeve 2 when installed as shown in
2 has a slight radial inward of the members 10A, 10B essentially to keep the body members 10A, 10B aligned with the holes 12A, 12B arranged essentially coaxially as shown. Gives a great compression force. Body member 10A, 1
FIG. 2 also shows a pair of capillary columns 25, 26 with ends mounted in holes 12A, 12B of FIG.
Is shown in In the example shown in FIG. 2, each capillary column 25, 26 has a corresponding hole 12 without additional provision for securing the column in the hole.
A and 12B are pressed and fitted. For those applications requiring additional securing force, a suitable adhesive may be applied between the outer surface of one or both of the capillary columns 25, 26 and the surface of the wall of one or more holes 12A, 12B. Can be applied. To facilitate bonding, the surface of the wall of a given hole 12 can be provided with non-uniformities, for example, by forming small grooves to provide depressions for the adhesive. In addition to the microgrooves, the surface of the holes can be rugged or randomly scored for the same purpose.

Referring to FIG. 4, two body members 10 are provided.
When A and 10B are aligned with their surfaces 20A and 20B in contact with each other, the axial holes 19A and 19B
They are aligned so as to form a passage extending therethrough. Most importantly, when a pressing force is applied to the main body members 10A, 10B so that the members 10A, 10B are pressed against each other, the radii of curvature 20A, 20B are deformed so as to move around the holes 19A, 19B. Is to form the fluid-sealed region 30 in the first step. This fluid-sealed area 30 can have an irregular profile, but this area is
It is only necessary to completely surround the hole opening exposed at 0A, 20B. The exact shape and extent of the sealing area 30 depends on the pressing force and the elasticity of the material.

In some applications, the body member 10 is provided with a pressing force large enough to deform the end surfaces 20A, 20B.
The sealing area 30 can be formed by hand on the opposite ends of the A, 10B and using a split sleeve that provides sufficient frictional force to hold the body members 10A, 10B together in a deformed state. it can. In many applications, it is desirable to deform the body member face-to-face to maintain a fluid-tight state,
Or, it is necessary. FIG. 5 shows an arrangement including an annular sleeve housing 35 wrapped around the split sleeve 22 and a pair of symmetrically disposed pressing force imparting mechanisms indicated generally by reference numerals 40A and 40B, respectively. ing. Referring to the mechanism 40A, the spool-shaped internal member 41 applies a translational force to the main body member 1 as shown in FIG.
It has inwardly directed ribs 42 that transmit rightward to 0A. The ribs 42 may include one or more teeth, a single circular rib, or a plurality of arcuate ribs. The spring locking flange 43 facing outward in the radial direction is
An internal locking portion for a biasing spring 45 attached around the outer peripheral surface of the inner member 41 is formed. Outer housing 46 is rotatably mounted on annular support member 48 by a plurality of ball bearings 49. Support member 48
Is provided with a wavy spring 51 which is frictionally fitted on the split sleeve 22 and generates a pressing force radially outward on the ball bearing 49.

In the case of mounting, the sleeve housing 35 is arranged around the split sleeve 22 and the wave spring 51 is arranged around one end of the split sleeve 22, to which the support member 48 and the assembly 40A, 40B
Followed by a housing 46. As assembly 40A is moved to the right (assembly 40B is moved to the left), outer end 14 of body member 10A contacts rib 42. The continuous axial movement in the direction of the facing surfaces 20A, 20B causes the spool 41 to move axially inward, compressing the spring 45 and compressing the surfaces 20A, 20B to maintain a deformed state. A sufficient axially inwardly directed force is applied. In the case of release, surfaces 20A, 2
OB loosens toward the structure where the curvature is formed by the elasticity of the material from which the main body members 10A and 10B are manufactured.

One of the significant advantages of the present invention is that the curved surfaces 20A, 20B form a liquid tight seal around the apertures 19A, 19B when the surfaces 20A, 20B are compressed and deformed together. Ability. This eliminates the need for a sealing gasket and eliminates the problems of gasket misalignment and aging, extreme temperature changes, and degradation due to exposure to solvents, diluents, and other chromatographic materials. In addition, the body member 10 is very simple in construction, durable and relatively inert to chemicals. The assembly is relatively simple to assemble, and the capillary column is
Can be easily inserted into (or removed from) the axial hole 12 of the device.

The present invention uses the method shown in FIGS.
It can be applied to make connections between capillaries or to make connections between capillary columns and injector liners, detector inserts and other suitable device components. For example, as shown in FIG. 6, the main body member 10 can be attached to the opened protrusion 55 of the injector main body 56 having the flow path 57 by the split sleeve 22.

Similarly, as shown in FIG. 7, the main body member 10 can be connected to an opening notch 58 of an injector main body 56 having a flow path 57. An aggressive mounting mechanism can be used to provide an inward pressing force to move member 10 into notch 58.

In addition to this, as long as the compressive strength and elasticity of the two different materials are sufficiently compatible to form the required fluid seal, the body member 10A made of zirconia can be used. Body member 10 made of silica
Body members formed from different materials, such as B, can be paired.

FIG. 8 shows an alternative structure for mechanically attaching a capillary column to a body member. As can be seen from this figure, the body member 60 has an enlarged outer threaded portion 62. A compressible ferrule 64, made of any suitable material, is received around the outer surface of the capillary column 25. An internally threaded cap 66 having an enlarged through hole 67 to accommodate the outer diameter of the capillary column 25 is threadedly attached to the portion 62 of the body member 60. This structure functions in a conventional manner to compress ferrule 64 as cap 66 is screwed into portion 62 of body member 60. In particular, the tapered nose portion of ferrule 64 is received within flared opening 68 and seals between ferrule 64 as inner surface 70 of threaded cap 66 is compressed. To form

Although the present invention has been described with reference to body members 10A, 10B having facing surfaces 20A, 20B, each having a positive curvature, in certain applications, as shown in FIG. In combination with the main body member having
A body member 10 having a flat surface can be employed. In particular, FIG. 9 is indicated generally by the reference numeral 75,
Flat surface 7 formed substantially perpendicular to bore axis 12
6 shows a positive curvature end surface 20A in contact with a body member having a 6; As will be appreciated by those skilled in the art, the body member 7
5 may include an independent body member, or a part of the injector liner, detector insert, or injector body. Also, the flat surface 76 may include the surface 59 of the notch 58 of the embodiment of FIG.

While the above description is thorough and complete, the present invention will recognize various modifications, alternative constructions, and equivalents. For example, the main body member 10
Although described with reference to a perfect circular cylindrical structure, other structures may be appropriate depending on the application. Also, if desired, another pressing mechanism such as a simple clamp can be employed. Therefore, the above description should not be construed as limiting the invention, which is defined by the appended claims.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a single connector incorporating the present invention.

FIG. 2 is a sectional view showing two such connectors aligned together by a split sleeve with an attached capillary column.

FIG. 3 is an end view of a split sleeve.

FIG. 4 is an enlarged detail view illustrating curved surface compression.

FIG. 5 is a cross-sectional view of the assembly of the present invention.

6 is a cross-sectional view showing the connector of FIG. 1 directly connected to a part of the analyzer.

FIG. 7 is a sectional view similar to FIG. 6, showing the use of the present invention in a notch opening for an analyzer.

FIG. 8 is a cross-sectional view of an alternative assembly.

FIG. 9 is an enlarged detail illustrating a curved surface compression between a curved surface connector and a flat surface connector.

[Explanation of symbols]

 10, 10A, 10B Body member 12, 12A, 12B Hole 14, 15 End 17 Inlet 18 Taper 19 Hole 20 Inner surface 22 Split sleeve 23 Slot 25, 26 Capillary column 35 Housing 40, 40A, 40B Pressing force Giving mechanism 41 Internal member 42 Rib 43 Flange 46 Outer housing 48 Support member 49 Ball bearing 51 Wavy spring

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 30/60

Claims (2)

(57) [Claims] 1. A connector for connecting a capillary column to another column, the connector having a first end and a second end, wherein the first end and a second end are connected to each other.
And a body member having an internal hole dimensioned to accommodate the end of the capillary column in a liquid-tight manner, the body member having One of the first end and the second end is
A connector having a curved surface that is slightly deformable when brought into contact with the second connector surface and forms a fluid seal without the need for a sealing gasket. 2. A connector assembly for forming a sealed fluid connection between a pair of capillary columns, wherein each member comprises a first end, a second end, and the first end. A pair of body members having an internal bore extending between the portion and the second end and dimensioned to receive an end of an associated capillary column in a liquid-tight manner, at least One of the first end and the second end of one of the main body members has a surface with a curvature, and the pair of main body members is connected to the other facing end of the main body member. Means for sealingly contacting under slight deformation to maintain alignment with respect to said curved surface.